Fuel injection valve



May 28, 1963 H. KNAPP ETAL 3,091,405

FUEL INJECTION VALVE Filed June 11, 1962 W n/r04 5 HE/NIQ/CH KNAPP 5 RUDOLF K/YA/JSS JOACH/M HE/SER Azfomevs United States Patent 3,091,405 FUEL INJECTION VALVE Heinrich Knapp, Leonberg-Silberherg, Rudolf Krauss,

Stuttgart-Wed im Dorf, and Joachim Heiser, Bernhausen, near Esslingen, Germany, assignors to Robert Bosch Gesellschaft mit beschrankter Haftung, Stuttgart, Germany Filed June 11, 1962, Ser. No. 201,57 8 Claims priority, application Germany June 15, 1961 9 Claims. (Cl. 239-453) The present invention relates to a fuel injection valve, more particularly, to such a valve which can be mounted within the open end of a fuel line.

The conventional fuel injection valve comprises a valve body and its operating components which valve is then suitably connected to the end of a fuel line. The valve is positioned on the engine in such a manner that the valve opening will periodically spray fuel into the combustion chamber of the engine.

While many forms of such injection valves have been devised such valves have all been characterized by comprising a separate unit which is mounted to the end of a fuel line leading from the fuel injection pump mounted on the engine. Such valves tend to be complex in structure thereby increasing maintenance problems and thus being relatively expensive to manufacture.

It is therefore the principal object of the present invention to provide a fuel injection valve which can be inserted into the open end of the fuel pressure line.

It is a further object of the present invention to provide a simplified but inexpensive fuel injection valve which is mounted within the fuel line in such a manner that the fuel line comprises the valve body of the valve.

The objects of the present invention are achieved by utilizing that portion of the fuel line adjacent the open end thereof as the valve body. A needle valve is slidably retained within the fuel line and opens toward the direction of the flow of fuel therethrough. Mounted on the other end of the needle valve is a valve member which is engageable with the open end of the fuel line which thus defines a valve seat. To urge the valve member against the valve seat and to thereby close the open end of the fuel line there is provided a spring member having a substantially stirrup-shape. The free ends of the spring member are attached to openings made in the outerwall of the fuel line and the closed end of the spring member is again bent to engage the valve member.

Structure is provided to retain the free ends of the spring member in position on the valve body and structure is also provided in the bore of the fuel line to retain the needle valve therein when the spring is removed.

Other objects and advantages of the present invention will be apparent from the accompanying description when taken in conjunction with the following drawings which are in greatly enlarged scale wherein:

FIGURE 1 is a side view of the fuel injection valve of the present invention;

FIGURE 2 is a longitudinal sectional view taken along the line IIII of FIGURE 1;

FIGURE 3 is a transverse sectional view taken along the line III-III of FIGURE 2.

With reference to the drawings wherein like reference symbols indicate the same parts throughout the various views a specific embodiment of the present invention will be described in detail. A fuel line whose end portion is utilized as the valve body of the fuel injection valve of the present invention is indicated at 1 with the bore of the fuel line having an enlarged diameter as indicated at 2 adjacent the end of the line.

A needle valve which is indicated at 3 is slidably mounted within the enlarged bore 2 and comprises two sections 4 and 5 each of which has a cruciform cross-section as may be seen in FIGURE 3. The forward end of the valve section 4 is pointed as indicated at 4a and points toward the direction from which the fuel in the fuel line flows as indicated by the arrow 19. The two valve sections 4 and 5 are separated by an annular groove 6.

The needle valve 3 is provided with a valve member 7 at its discharge or outlet end. The valve member 7 is urged by means of a spring 8 into closing position against a valve seat 9 which is formed at the open end of the valve body 1.

Reference to FIGURES 1 and 2 shows that the spring 8 is substantially U-shaped with the two legs indicated at 11 being in divergent relationship to each other and the free ends of the legs being bent at substantially right angles as shown at 10. The closed end of the spring indicated at 8a is bent upwardly as may be seen in FIGURE 1 and is received within a recess 7w made in the end of the valve member 7. The closed end 802 of the spring thus urges the valve member 7 against the valve seat 9 to close the valve. This closed position of the valve as illustrated in the drawings is the normal position thereof, and the valve is opened in a manner to be subsequently described.

The bent ends 10 of the spring 8 are inserted into radially positioned transverse bores 12 which are substantially opposed to each other. These bores 12 terminate short of the valve body bore 2.

To retain the spring ends 10 within the bores 12 a tubular casing 14 is mounted upon the valve body 1. The tubular casing is secured to the valve body by fitting an annular groove 13 thereof made adjacent one end of the tubular casing into an annular recess 16 formed in the outer wall of the valve body. The other end of the tubular casing is provided with a pair of enlarged portions 15 which receive the bent ends of the spring member as may be seen in FIGURE 2 and retain the bent ends within the bores 12.

There are also provided two additional radial bores 17 in the valve body 1 and extending toward the bore 2 but terminating short thereof. The bottoms of these bores as indicated at 18 are bulged inwardly toward the center of the bore 2 so as to extend into the annular groove 6 of the needle valve 3'. These bottoms which are bulged after the needle valve has been inserted retain the needle valve within the bore 2 in the event the spring 8 is broken or removed. While two bores 17 have been shown it is pointed out that even one bore may be suflicient or in some cases more than two bores may be employed.

The fuel which is to be inected into the combustion chamber of the engine is supplied to the injection valve by means of a fuel injection pump (which is not illustrated in the drawings) in the direction of the arrow 19. As soon as the fuel pressure exceeds the locking pressure retaining the valve member 7 in closed relationship upon the valve seat 9 the valve member will be lifted from its valve seat to permit the injection of the fuel into the engine. The pressure with which the valve member is held in closed position is determined by the force of the spring 8.

As soon as the fuel pressure decreases below the closing force of the valve member '7, again determined by the force of the spring 8, the valve member will close against its valve seat under the action of spring 8.

In the embodiment of the valve member 7 and valve seat 9 as illustrated and disclosed herein the closing pressure of the valve member differs only slightly from the opening pressure.

I Because of the small size of the needle valve 3 and the components thereof the mass of the needle valve will be quite small. As a result the valve member 7 Will open and close very rapidly during the injection process. As a result a satisfactory spraying of the fuel into the combustion chamber of the engine is obtained with the fuel injection valve of this invention.

H Further, in view of thelow mass of the injection valve disclosed herein the valve member can rapidly follow the fluctuations in fuel pressure as established by the fuel injection pump.

Thus it can be seen that the present invention discloses a simplified yet effective fuel injection valve for the injection of fuel into an engine directly from the fuel line. The injection valve can be readily inserted into the open end of a fuel line and the entire construction is so simple that the manufacturing expenses of such a valve are held to a minimum.

It is to be borne in mind that although the present valve is particularly adapted for a fuel injection line this valve construction is susceptible to a wide variety of applications.

It Will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions, and, accordingly, it is desired to comprehend su'ch modifications within this invention as may fall within the scope of the appended claims.

What is claimed is:

1. A valve comprising a valve body having an axial bore therein and opening at one end of said body to define a valve seat, a needle valve slidably mounted in said bore and having a valve member engageable with said valve seat, and a substantially U-shaped spring with the closed end thereof being bent, the open end .of said spring being attached to said valve body and the bent cloned end engaging said valve member to urge the same against said valve seat to close the valve.

2. A valve comprising a valve body having an axial bore therein and opening at one end of said body to define a valve seat, there being a pair of radially extending recesses in said valve body, a needle valve slidably mounted in said bore and having a valve member engage'able with said valve seat, and a substantially U- shaped spring with the closed end thereof being bent, the open end of said spring consisting of tWo free ends which are inserted "into said radially extending recesses to attach the spring to the valve body and the bent closed end engaging said valve member to urge the same against said valve seat to close the valve.

3. A valve comprising a valve body having an axial bore therein and opening at one end of said body to define a valve seat, there being a pair of radially extending recesses in said valve body, a needle valve slidably mounted in said bore and having a valve member engageable with said valve seat, an elongated spring element bent into substantially a U-shape with the closed portion of the U-shape being bent and the free ends of said spring elementsbeing bent substantially at right angles, the bent free ends of said spring element being positioned in said radially extending recesses to attach the spring element to the valve body and the bent closed portion of the spring element engaging said valve member to urge the same against said valve seat to close the valve.

4. A valve comprising a valve body having an axial bore therein and opening at one end of said body to define a valve seat, there being a pair of radially extending recesses in said valve body, a needle valve slidably mounted in said bore and having a valve member engageable with said valve seat, an elongated spring element bent into substantially a U-shape with the closed portion of the U-shape being bent and the free ends of said spring element being bent substantially at right angles, the bent free ends of said spring element being positioned in said radially extending recesses to attach the spring element to the valve body and the bent closed portion of the spring element engaging said valve member to urge the same against said valve seat to close the valve, and a tubular casing mounted on said valve body with one end of said casing being positioned over the bent free ends of said spring element to retain said bent ends within said recesses.

5. A valve comprising a valve body having an axial bore therein and opening at one end of said body to define a valve seat, a needle valve slidably mounted in said bore and having a valve member engageable with said valve seat, there being an annular groove around said needle valve, a substantially U-shaped spring with the closed end thereof being bent, the open end of said spring being attached to said valve body and the bent closed end engaging said valve member to urge the same against said valve seat to close the valve, there being projections on the Wall of said bore and extending into said annular groove to retain said needle valve within said bore when said spring is removed.

6. A valve comprising a valve body having an axial bore therein and opening at one end of said body to define a valve seat, a needle valve slidably mounted in said bore and having a valve member engageable with said valve seat, there being an annular groove around said needle valve, asnbstantially U-shaped spring with the closed end thereof being bent, the open end of said spring being attached to said valve body and the bent closed end engaging said valve member to urge the same against said valve seat to close the valve,there being at least one additional radial recess in the valve body with the bottom of said additional recess bulging into said annular groove to retain said needle valve Within said bore When said spring is removed.

7. A valve comprising 'a valve body having an axial bore therein and opening at one end of said body to define a valve seat, there being a pair of radially extending recesses in said valve body, a needle valve slidably mounted in said bore and having a valve member engageable with said valve seat, there being an annular groove around said needle valve, an elongated spring element bent into substantially a U-shape with the closed portion of the U-shape bei-ng bent and the free ends of said spring element being bent substantially at right angles, the bentfree end-s of said spring element being positioned in said radially extending recesses to attach the spring element to the valve body and the bent closed portion of the spring element engaging said valve member to urge the same against said valve seat to close the valve, there being at least one additional radial recess in said valve body with the bottom of said recess bulging into said annular groove to retain said needle valve Within said bore when said spring is removed.

8. A valve comprising a valve body having an axial bore therein and opening at one end of said body to define a valve seat, there being an opposed pair of radially extending recesses in the outer wall of said valve body, a needle valve slidably mounted in said bore and having a valve member on one end thereof engageable with said valve seat, there being an annular groove around said needle valve, an elongated spring element bent into substantially a U-shape with the closed portion of the U- shape again being bent and the free ends of said spring element being bent at substantially right angles, the bent the same and the bent free ends of said spring element i being positioned in said recesses to attach the spring element to the valve body, a tubular casing fastened upon said valve body with one end of said casing having enlarged portions therein with said enlarged portions being positioned over the bent free ends of said spring element to retain said ends Within said recesses, there being at least one transversely extending bored recess into the Wall of said valve body but terminating short of said bore With the bottom of the recess adjacent said bore being bulged into said annular groove to retain said needle valve within said bore when said spring element is removed.

9. In combination with the open end of a tubular fuel line, a needle valve slidably retained Within said tubular line and having a valve member engageable with the open end of said line, a substantially U-shaped spring with the closed end thereof being bent, the open end of said spring being attached to the outer wall of said fuel line and the bent closed end engaging said valve member to urge the same against said fuel line open end to close the line.

References Cited in the file of this patent UNITED STATES PATENTS Miller July 2, 1878 

1. A VALVE COMPRISING A VALVE BODY HAVING AN AXIAL BORE THEREIN AND OPENING AT ONE END OF SAID BODY TO DEFINE A VALVE SEAT, A NEEDLE VALVE SLIDABLY MOUNTED IN SAID BORE AND HAVING A VALVE MEMBER ENGAGEABLE WITH SAID VALVE SEAT, AND A SUBSTANTIALLY U-SHAPED SPRING WITH THE CLOSED END THEREOF BEING BENT, THE OPEN END OF SAID SPRING BEING ATTACHED TO SAID VALVE BODY AND THE BENT CLOSED END ENGAGING SAID VALVE MEMBER TO URGE THE SAME AGAINST SAID VALVEW SEAT TO CLOSE THE VALVE. 